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September 04, 2009

A Deep Dive into IP Voice Peering

By Doug Mohney, Contributing Editor

Business VoIP carriers currently operate as standalone islands when it comes to voice traffic. A group of them have recognized it is in their mutual self-interest to join together and work out an IP peering “fabric” as an alternative to the existing PSTN. Depending on the day of the week, I’ve heard there’s going to be anywhere from a dozen firms to over thirty-plus firms, including some larger CLECs. The goals are to bypass the traditional PSTN and support advanced SIP-based services

Everyone – outside of those selling wholesale IP and transit services – seems to agree that being able to build and grow a large community of G.722 wideband users would be a good thing to get high-quality voice usage moved forward in North America. A number of hosted business VoIP carriers, such as Alteva (News - Alert) and Simple Signal, support HD voice in the form of the G.722 wideband codec. Using G.722 provides call fidelity akin to FM radio – a big leap from the stock, less than AM-radio quality, PSTN phone call standard that hasn’t changed all that much since 1937.

Conceptually, it all sounds good, but there are some not very nice things that the Internet peering “gray beards” have discovered over the years. IP peering has been taking place since the early ‘90s and the process has not been all sweetness and light. During the “Effective IP Peering Strategies” discussion at ITEXPO this week, gurus from TATA Communications and Mzima (News - Alert) Networks shed light on various models for peering and behind-the-scenes headaches involved when you combine network hardware with human fallibility and corporate egos.

Sylvie Laperrière, Director, Peering & Commercial Operations for TATA Communications, noted that her company conducts a restrictive peering model, due in part to being a Tier 1 carrier. If a carrier wants to exchange packets with TATA as an equal, they need to be able to connect to TATA’s network on at least six high-speed exchange points and offer a data packets ratio of around two to one. If said carrier is shipping over around 1 to 2 Gbps of packets per second, TATA should be able to send around the same amount to derive sufficient benefit from the networking arrangement.

Mzima Networks has a different model, which CTO Grant Kirkwood (News - Alert) calls “Donut peering.” Instead of going through Tier 1 peers at the core (donut hole) of the network, Mzima creates bilateral links to numerous high-speed broadband providers – around a thousand at last count – to create the “donut” around the core. Donut-style peering is, however, much more relationship and management intensive when compared to the 58 or so Tier 1 peering relationships that TATA has established.

Regardless of the model, peering is not for the light-hearted. First, since each peer has primary access to the routing tables of everyone else, one misconfigured router can bring everyone down, resulting in a major service interruption. Peering partners need to bring their “A” game in terms of personnel, experience, and practices. Laperrière said minor glitches occur around once a month, but noted more major service interruptions are not unheard of, pointing to an incident this spring where a Pakistani ISP tried to filter access to YouTube (News - Alert) and ended up cutting off the Google video site completely off the internet for around two hours until workarounds could be put into place. .

More significantly, peering is much more of a marriage than a business relationship than people seem to understand. If two companies sever a business relationship, only rarely do customers suffer. When two peers fight and one decides to shut down bilateral peering connections, all of the downstream “children” – paying customers – of both customers suffer because they suddenly do not have access to companies sitting on the other network. Email, web access, and VoIP calls delivered between the two peers suddenly can’t find sites and everyone starts to get ugly. Last year, Cogent Communications and Sprint (News - Alert) ended up in a business dispute that lead to Sprint briefly pulling the plug on the peering relationship. Customers of both companies were not happy and the link was re-established after a few days of pain on all sides.

Given the occasionally checkered history of IP peering relationships across the years, I’m hoping that the hosted business VoIP community truly understand what it is getting into. Today, everyone is happy and talking “coopetition,” but with a dozen or thirty some or more parties involved I’m not going to be surprised if there are a few ugly divorces along the way.

Doug Mohney is a contributing editor for TMCnet and a 20-year veteran of the ICT space. To read more of his articles, please visit columnist page.